I think these ESC's are coming out soon (this month). They include data recording (I guess of the motor parameters like volts, current and rpm), but I am not sure what else is inside their programming. If it also includes the standard Phoenix firmware for the governor, then it looks pretty nice.

What surprised me was the price. At Tower the 50A version is ~$85, which is about what I paid for my Phoenix 45. There are two versions, a "lite" and a normal. The normal looks like it has a heat sink, but it also weighs 1.22 oz. I'm not sure on the weight of the "lite" version.

This seems like an incredibly good deal (unless I am missing something).

Nice, the built in datalogging capability's is something I really want. Right now I'm trying to convince myself that I really need an EagleTree logger with rpm and temp. sensor. 

Alan, buy an "ICE Esc" and try it out, then tell the rest of us if we need them 

/Andreas

Yeah Alan, I'm looking forward to getting some info on those too. Sounds like a good candidate for my Jenny ESC. The Jenny will need some nose weight, so I'm also seriously considering A123 batteries in a 6S format (19.8V)for a first foray in to a higher voltage setup. I suspect there will be a gradual move to higher voltage battery pack since it pays a capacity dividend from the lower current. The guys flying large scale RC electrics are already there. Having a reasonable cost HV ESC is going to be a boon.

When I was building electric vehicles, we ended up with 148 V battery packs since lead acid batteries are strongly affected by the losses of their internal resistance.

John

Well as I have maintained for a long time, there is no difference between six cells hooked up in series (as a 6s1p pack) or hooking them up as a 3s2p, or even a 2s3p pack, as long as you adjust the kV of the motor, and the ESC current capability, at least with regards to the internal resistance of the cells.

Look at it this way, if you are pulling the same wattage out of each cell (so you are getting the same wattage from each pack), the current from each cell is just the same, and the power lost in the cell due to resistance is just equal. The net result is that there is no difference, even though you have twice the current from the 3s2p, and three times the current in the 3s3p packs as the 6s1p pack. Of course you would want to use a larger gauge hookup wire in the two former packs to keep wire losses the same.

Back in the old days (which may end soon), a 6s ESC (aka an "HV" ESC) cost more than the "normal" ESC, so a 70A ESC wasn't that much different than a 35A HV ESC, and you had to buy an external BEC to boot (for the 6s type packs). However these new ICE ESC's seem to remove that cost differential (if I understand what they are saying), so it does appear that we may be moving to the higher voltages as the cheaper way to go in the future.

Just my guesses.

As long as you adjust kV to meet the pack voltage, everything stays the same.

So a 3s pack typically works well with kV's in the 1000-1100 rpm/volt range. If you went to a 6s pack, then you would want a kV ~500-550 rpm/volt. (this will depend on what rpm you want to run a prop at--I am talking about low 8000's for me).

So to quickly illustrate how it doesn't matter, the only difference between the kV=1000 and the kV=500 is that the 500rpm/V motor has twice the number of winds as the 1000 rpm/V motor. Since 1/2 the amps will flow in the 6s case, the double the number of winds exactly compensates the lower current. The magnetic field an electromagnet makes is proportional to the current x the number of winds.

Now to show that the resistive losses are the same, the 500kV motor has twice the length of wire  (just from twice the # winds). Assuming the 1000 kV stator is completely packed with copper, the only way to increase the number of winds is to use thinner wire. Ideally, you would use a wire which had 1/2 the cross-sectional area---so in the end, the 500kV stator is also packed as fully as you can get. So with twice the length, and half the cross-sectional area, the resistance of the 500kV motor is 2x2=4 times higher than the 1000kV motor.

That sounds bad, but remember the 500 kV motor has 1/2 the current (but twice the voltage so the watts are the same). The heating inside the motor is I²*R, I being the current. Well with 1/2 the current, and 4 times the resistance, the heating (1/2I)²*4R = I²R, just the heating in the 1000kV motor.

So you can mix and match things by scaling the pack voltage and the motor kV to find equivalent setups--whatever is convenient.

The only proviso is keeping track of the ESC capability (volts and amps). The other deal is the connecting wire, which to be exactly scaled, means you need twice the cross-section of the connecting wire for the high current case. But the resistance of the connecting wire is pretty darn small in most cases, and you can usually ignore it.

So we see the battery doesn't care, and the motor doesn't care, so choose what you want---usually the choice is a function of what you can buy or already have. That's why I sometimes hook up two 3s2100 packs in parallel (~like a 3s4200 pack) and run my 1100kV motor--especially when I am not sure how much battery capacity I need for a new plane. Then after I establish what I need, I usually can find a smaller pack (4s2100 or 5s2100) that will satisfy the energy needs. Then for the best efficiency, I try to find an equivalent kV motor.

Bob,

Basically you are right that simply reshuffling the pack from a 3s to a 4s--without changing the motor too--will give you problems. However lowering the motor kV to adapt to the 4s pack won't bring you any gains either. I assume you want more speed at the high end, and maybe a little more capacity --but no more weight either.

So to illustrate the problem: Compare a 3s2600 pack (20C) to a 4s1950 (20C) pack ( both carry the same energy (3x2600=4x1950), the 4s pack max current is ~39A while the 2600 max current is 52A (close to your 55A static draw). Both can supply the same output watts (volts*amps), and if the individual cells were made with the same technology, I amclaiming that the internal heating (resistive losses) would be the same for the same output wattage.

However you need a certain amount of amps (which translates directly to torque) to turn the prop at the rpm you are now getting at full throttle with the 3s system. So that is going to put the 4s pack at some disadvantage. For the sake of argument, I'll assume the internal resistance of each cell is just inversely proportional to the capacity, so a single 1950 cell will be 4/3 the resistance of the 2600 cell (that's why I say we assume the same technology was used to make each cell). In addition there are 4 cells instead of the 3, so the 4s1950 pack has 16/3 R and the 3s2600 pack has 3R resistance (R=resistance of a single 2600mAHr cell).

Net result is that the 4s pack has 16/9 the resistance of the 3s pack (almost a factor of 2). This means that the voltage out of the 4s pack will have almost twice the voltage drop that the 3s pack experiences for the same current. Corollary is that it will also experience roughly twice the heating that the 3s pack experiences.

Another fact is that with the extra cell, you probably will get (at least initially) more than the ~55A out of the 4s pack at full throttle, and then of course the heating is worse. Since heat left in the battery is energy not supplied to the motor, and you say that the 3s2600 currently just has enough, my guess is that you may not have enough with a 4s1950 pack to finish the entire flight. In any event I don't see any advantage


One way around this is to go to newer technology batteries----These days I see 35 and 40C batteries. From my limited understanding of lipo's, the higher C represents a lower internal battery resistance (also may represent marketing hype!). I also notice that higher C tends to be higher weight too so you would always have to take that into account.

The lower internal resistance means that you will have a higher voltage output to the motor, which translates to more watts into the motor, and presumably to a higher initial speed. Of course you need to be careful that you don't overburn at high speed leaving too little in the pack for the full flight.

So readjusting for what you want--I guess you want more at less weight. Anything you can do to lower the battery internal resistance per cell means you have more to give to the motor--assuming the weight doesn't change. I have heard some really good things about some of the newer battery technologies--from people who seem to know and also have made independent measurements.

Here is a link to some of the testing being done with the newer cells (this is on RCGroups). I think the point from the test was that here are 4 manufacturers who have some pretty good cells.

http://www.rcgroups.com/forums/showthread.php?t=1087837

These were 3s2200 cells, so to get the capacity you need you would need a 4s pack, and a motor with a kV ~3/4 of your current setup. However they probably have higher capacity packs too.

So I still claim that there is no inherent advantage (like in efficiency)  to go up in Voltage. However if you simply want more performance with the same kV motor, then more voltage will force more current through the motor,  but then you will need to  carry more weight (=fuel)!

Hope this was of some help. I didn't really answer your question. I think to do that we would need some actual cell resistances and try to calculate how much energy is left in heating up the battery, and then add capacity to take that into account.

I think there was an "issue" with the Thunderpower Extreme V2 losing capacity quite early. Quite a few unhappy people (going by the response in the forums).

These new ones seem really pretty good and not just the Thunderpower Pro's either.

I really haven't found any details on how the ICE ESC are setup, so I guess I would hold off getting one until I knew more about them (like they will have a CL mode for example). Not that they won't, but the initial info is somewhat vague. Also it doesn't hurt to be the second kid on the block to get one (after the first kid takes the risk!).

Crist,
I'm not sure that the "Ice's" weigh all that much more than the "normal" Phoenix. I'm talking about the "Lite"'s  (Lites on Ice---hmm, sounds good). I also think an ICE is a Phoenix---on steroids, but until they put out more info, I am not sure.

One advantage (in principle) is that you can go to 6s and 50A for the ICE Lite 50 and it seems to cost about what the Phoenix 45 costs.

Also to be honest, I don't fly that often with my Eagle Tree either. It is somewhat of a pain to put it in the Vector (I had more space in the Nobler). In that sense, the ICE would be more convenient--but I don't really need another ESC right now.

However it probably is useful to take a record every so often just for my own edification---especially after the trimming has settled down.

added after: If I believe the CC specs, the Phoenix Ice Lite 50 is 0.8oz compared to 1.0oz for the Phoenix 45, so it is actually lighter.

Andreas,
Yup, you're right about the 50A Lite.     I thought that the ICE were almost an ounce heavier.  I stand corrected.  Besides the price they look pretty good.

Alan,

I decided to move the ICE conversation to this thread.

The logger will record %power/throttle, watts, amps, voltage, cum mah, ripple voltage, rpm, & controller temp.  I think that's it. LOL  I don't think that is what you are looking for.  let me play with the graphs and I'll post something.

What I like is that it dosen't matter how many poles you select.  You can change the value after recorded unlike the Eagle tree.  Nothing makes me angrier than accidentally selecting or forgetting to change the pole count before logging.  I also like the graph viewer in Castle Link.  It displays live values for the data based on cursor position.  You also don't get the start-up spikes that you get on the Eagle Tree.  All in all, the ICE logger is the real deal. 

Archie Adamisin
Muncie, Indiana

Archie,
I asked the question in the CC forum on RC Groups and Patrick del Castillo told me the parameter is there--it's the "Motor Output Power".

So that's cool. If you would like to know how close you are to maxing out the governor, you can find out. I guess I might have to get one of the ICE 50's. I'm thinking by monitoring that parameter, you would also get an idea how your battery is holding up over a season. Once you start kissing the 100% range (and as a result not being able to hold rpm in a climb near the end of a flight), that battery is becoming toast!

I tried to buy one today from Hobby People. They would give me free postage, but the ICE lites are not in stock, and unfortunately the offer isn't good (they say) for back orders.

Humm, I just ordered a Phoenix 50 ICE ESC from Atomic Hobbies & Games For $84.99 but with free shipping. Guess that works out to be about the same.